How can the vacuum sintering process be performed correctly?

Vacuum sintering is one of the unsung heroes of industrial metallurgy. In this vital process, materials are heated to near melting point in a vacuum environment. After heating, the material becomes dense and acquires completely new properties.

How can vacuum sintering be performed correctly?
This article will provide a powerful help for customers who want to adopt this process. First: Why vacuum sintering? Vacuum sintering involves two important aspects: the vacuum furnace and the metal powder. If the vacuum furnace is used correctly and the metal powder is mixed in the right proportions, a variety of desirable properties can be achieved. For example, some of the metal compounds produced by sintering can reduce the failure of machine or automobile parts. It can also produce parts that require high porosity, such as pipe parts and system parts involving ball bearings. Therefore, if you need to strengthen a product, or improve its porosity, sintering is usually the best option. However, it is important to remember that sintering must not be performed before another important process: debinding. Both processes should be considered together when making equipment purchase plans.

Debinding: Necessary preparation for vacuum sintering
Debinding: Necessary preparation for vacuum sintering Debinding is the preparation of a material or component for vacuum sintering. Debinding must be sufficient. All components contain impurities, usually from the injection molding process. If these impurities remain on the surface of the component, they can easily affect the effectiveness of debinding. Debinding is the removal of “binders” deposited during the production process. If debinding is not sufficient, it will cause the surface of the component to peel or produce holes that cannot be eliminated by sintering. Therefore, it is very important to perform debinding correctly. The process regime for debinding depends entirely on the type of binder. Regardless of whether special solvents are used in the binder, the decomposition of organic binders almost always occurs during heat treatment at temperatures of usually 150°C– 600°C. In order to ensure that all binders are completely removed, it is often necessary to perform multiple treatments in the furnace. This operation must be done carefully, because even trace residues can contaminate the sintering process. At this point, an important question must be considered: Can the same vacuum furnace be used for debinding and sintering? This question is crucial because it affects the cost and the possibility of success of the process. Therefore, this question is definitely worth careful consideration.

Should you combine your sintering and debinding furnaces?
There are several factors that should not be overlooked when making the decision whether to combine your sintering and debinding furnaces. First, it is important to consider the fragility of the parts. When the parts are debinded, the loss of binder and the heat can make the parts more fragile and more susceptible to damage than before. If many parts are moved between different processing furnaces, the possibility of damage and thus loss of parts can make the processing in the same furnace more favorable. However, it must be pointed out that a pre-sintering step in the debinding furnace can usually solve this problem. It is also crucial to ensure the cleanliness of the process. You do not want contaminants to affect the sintering furnace chamber at any stage. So, on the surface, sintering and debinding seem to conflict with each other. Debinding is about removing impurities, which is characterized by “dirty”. But this is not a big problem. In many cases, with the right process, the removed binder can be effectively separated from the sintering powder. Cost is also a consideration. Not all companies can afford to install a sintering furnace and a debinding furnace at the same time, especially if the amount of material being processed is relatively small. Time is also an important factor. Sintering is generally much faster than debinding, but the time difference between the two varies with the materials used. If the difference is too great, a much larger debinding furnace should be used to keep the line on a steady rhythm. In such cases, it is necessary to use separate sintering and debinding furnaces. Human resources must also be considered. In smaller production plants, combining the sintering and debinding furnaces into one allows for the most efficient use of human resources. Workers can be significantly more efficient because they do not have to operate two furnaces and move parts between them. Finally, there are energy costs. In many cases, combining two vacuum furnaces into one can improve energy efficiency and help reduce costs. If arranged properly, the heating and cooling required for the vacuum furnace – the main energy consumer in the process – can be greatly reduced. Therefore, there are reasons to combine or separate the debinding and sintering furnaces. Generally speaking, if you have very demanding debinding requirements or you are not particularly concerned about the fragility of the parts, it is recommended that the two furnaces be separated. However, if this is not the case, you may find that combining the two furnaces into one will reduce costs and save energy without compromising product quality.

Vacuum sintering furnace